WO2015146947A1

WO2015146947A1 - Additive for non-aqueous electrolyte, non-aqueous electrolyte, and power storage device

Info

Publication number: WO2015146947A1
Application number: PCT/JP2015/058827
Authority: WO
Inventors: 藤田　浩司; 恭幸高井; 佑軌河野
Original assignee: 住友精化株式会社
Priority date: 2014-03-28
Filing date: 2015-03-24
Publication date: 2015-10-01
Also published as: EP3131153A1; KR20160138402A; CN106133984A; US20170117588A1; TW201542519A; JPWO2015146947A1; EP3131153A4

Abstract

The purpose of the present invention is to provide: an additive for a non-aqueous electrolyte, the additive having an excellent storage stability and the capability, when used in a power storage device, of forming a stable solid electrolyte interface on the surface of the electrode and improving cell characteristics such as cycle characteristics, charge/discharge capacity, high-temperature storage characteristics, suppressed gas generation, and reduction in internal resistance, wherein the additive for a non-aqueous electrolyte contains a cyclic imide compound represented by formula (1-1), (1-2), (1-3), (1-4), (1-5), or (1-6); or to provide a non-aqueous electrolyte in which the additive for a non-aqueous electrolyte is used, and a power storage device in which the non-aqueous electrolyte is used.

Description

Non-aqueous electrolyte additive, non-aqueous electrolyte, and electricity storage device

The present invention relates to an additive for a non-aqueous electrolyte. The present invention also relates to a non-aqueous electrolyte containing the additive for non-aqueous electrolyte, and an electricity storage device using the non-aqueous electrolyte.

In recent years, research on non-aqueous electrolyte secondary batteries represented by lithium ion batteries has been extensively conducted as interest in solving environmental problems and realizing a sustainable recycling society has increased. In particular, lithium ion batteries are used as power sources for notebook computers, mobile phones and the like because of their high operating voltage and energy density. These lithium ion batteries have higher energy density compared to lead batteries and nickel cadmium batteries, and are expected to realize higher capacities.
However, the lithium ion battery has a problem that the capacity of the battery decreases with the progress of charge / discharge cycles and storage under high temperature conditions. This is due to the side reaction between the electrode and the electrolyte, the degradation of the electrolyte due to the electrode reaction, the impregnation of the electrolyte into the electrode active material layer, and the intercalation of lithium ions. Factors such as a decrease in the efficiency of the service are listed.

Methods for adding various additives to an electrolytic solution have been studied as a method for suppressing the decrease in battery capacity accompanying the storage of charge / discharge cycles and high temperature conditions. The additive is decomposed during the first charge and discharge to form a film called a solid electrolyte interface (SEI) on the electrode surface. Since the SEI is formed in the first cycle of the charge / discharge cycle, electricity is not consumed for the decomposition of the electrolytic solution, and lithium ions can move back and forth through the SEI. That is, the formation of SEI is considered to play a major role in preventing deterioration of power storage devices such as non-aqueous electrolyte secondary batteries when charging / discharging cycles are repeated, and improving battery characteristics, storage characteristics, load characteristics, etc. It has been.

As an additive for an electrolytic solution for forming SEI, for example, Patent Documents 1 to 3 include cyclic monosulfonic acid esters, Patent Document 4 includes sulfur-containing aromatic compounds, Patent Document 5 includes disulfide compounds, and Patent Document 6 9 to 9 respectively disclose disulfonic acid esters.
Patent Documents 10 to 13 disclose electrolytic solutions containing vinylene carbonate or vinyl ethylene carbonate, and Patent Documents 14 and 15 disclose electrolytic solutions containing 1,3-propane sultone or butane sultone. Has been.

JP 63-102173 A JP 2000-003724 A JP 11-339850 A JP 05-258753 A Japanese Patent Laid-Open No. 2001-052735 JP 2009-038018 A Japanese Patent Laid-Open No. 2005-203341 JP 2004-281325 A JP 2005-228631 A Japanese Patent Laid-Open No. 04-87156 Japanese Patent Laid-Open No. 05-74486 Japanese Patent Laid-Open No. 08-45545 JP 2001-6729 A JP 63-102173 A Japanese Patent Laid-Open No. 10-50342

As an index of the adaptability of non-aqueous electrolyte additives for electrochemical reduction in electrodes of non-aqueous electrolyte secondary batteries, for example, “Geun-Chang, Hyung-Jin Kim, Seung-ll Yu, Song-Hui Jun, Jong-Wook Choi, Myung-Hwan Kim.Journal of The Electrochemical Society, 147, 12, 4391 (2000) "shows the LUMO (minimum empty molecular orbital) energy of the compound constituting the additive for non-aqueous electrolytes. A method using a plurality of energy levels has been reported. In such a document, a compound having a lower LUMO energy is an electron acceptor that is more excellent, and is a non-aqueous electrolyte additive that can form a stable SEI on the surface of an electrode such as a non-aqueous electrolyte secondary battery. It is supposed to be. Therefore, by measuring the LUMO energy of a compound, it is possible to easily evaluate whether the compound has the ability to form stable SEI on the electrode surface of a nonaqueous electrolyte secondary battery or the like. Is now a very useful tool.

On the other hand, the compounds disclosed in Patent Documents 1 to 9 have high LUMO energy, insufficient performance as additives for non-aqueous electrolytes, and are chemically unstable even when LUMO energy is low. There was a problem such as. In particular, although the disulfonic acid ester compound exhibits low LUMO energy, it has a low stability to moisture and easily deteriorates. Therefore, when it is stored for a long period of time, it is necessary to strictly control the moisture content and temperature. Furthermore, for example, since a heat resistant temperature of about 60 ° C. is generally required for a lithium ion battery and about 80 ° C. for a lithium ion capacitor, the additive for non-aqueous electrolyte used in an electricity storage device is high. Improving the stability of was an important issue.

In addition, the performance of SEI formed on the electrode surface varies depending on the additive used, and is deeply involved in many battery characteristics such as cycle characteristics, charge / discharge capacity, high temperature storage characteristics, gas generation suppression, and reduction of internal resistance. . However, when conventional additives are used, it has been difficult to form SEI with sufficient performance and to keep its battery characteristics high over a long period of time.
For example, an electrolytic solution using a vinylene carbonate compound or a sultone compound such as 1,3-propane sultone described in Patent Documents 10 to 15 as an additive causes electrochemical reductive decomposition on the negative electrode surface. The generated SEI can suppress irreversible capacity reduction. However, although SEI formed by these additives is excellent in the performance of protecting the electrode, the performance of lowering the internal resistance is small because of the low ion conductivity of lithium ions. Further, the formed SEI does not have the strength to withstand long-term use, and the SEI is decomposed during use or the SEI cracks, so that the surface of the negative electrode is exposed and the electrolyte is decomposed. There was a problem that the characteristics deteriorated.

As described above, the conventional additive for non-aqueous electrolyte does not have sufficient performance over a long period of time in performance of protecting the electrode or reducing internal resistance, and there is room for improvement. . That is, a novel electrolytic solution that improves the battery characteristics of an electricity storage device such as a non-aqueous electrolyte secondary battery by forming SEI that is stable on the electrode surface and that improves cycle characteristics, charge / discharge capacity, internal resistance, etc. Development of additives for use was required.

The present invention is excellent in storage stability and, when used in an electricity storage device, forms a stable solid electrolyte interface (SEI) on the electrode surface to provide cycle characteristics, charge / discharge capacity, high temperature storage characteristics, gas generation suppression, internal It aims at providing the additive for non-aqueous electrolyte which can improve battery characteristics, such as reduction of resistance. Another object of the present invention is to provide a non-aqueous electrolyte using the additive for non-aqueous electrolyte and an electricity storage device using the non-aqueous electrolyte.

The present invention provides the following formula (1-1), formula (1-2), formula (1-3), formula (1-4), formula (1-5), formula (1-5) The additive for non-aqueous electrolyte solution containing the cyclic imide compound represented by −6).
In addition, the additive for non-aqueous electrolyte of the present invention is not limited to the one containing only the cyclic imide compound according to the present invention, and may contain other components as long as the object of the present invention is not impaired. .

R ¹ in formula (1-1), R ³ in formula (1-2), R ⁵ in formula (1-3), R ⁷ in formula (1-4), formula (1-5) R ⁹ in the formula and R ¹¹ in the formula (1-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms and an optionally substituted alkenyl group having 2 to 4 carbon atoms. , An optionally substituted alkoxy group having 1 to 4 carbon atoms, an optionally substituted phenyl group, an optionally substituted phenoxy group, an optionally substituted benzyl group, an optionally substituted benzyl An oxy group, an optionally substituted alkenyloxy group having 2 to 6 carbon atoms, or an NR ¹³ R ¹⁴ group, wherein R ¹³ and R ¹⁴ are each independently a hydrogen atom or an optionally substituted carbon; An alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms which may be substituted, A phenyl group which may be substituted or a benzyl group which may be substituted is shown. R ² in formula (1-1), R ⁴ in formula (1-2), R ⁶ in formula (1-3), R ⁸ in formula (1-4), formula (1-5) R ¹⁰ in the formula and R ¹² in the formula (1-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms and an optionally substituted alkoxy group having 1 to 4 carbon atoms. Or a halogen atom. L in the formula (1-1) represents an integer of 0 to 4, m in the formula (1-2) represents an integer of 0 to 2, and n in the formula (1-3) represents 0 to 2. Represents an integer, o in the formula (1-4) represents an integer of 0 to 4, p in the formula (1-5) represents an integer of 0 to 4, and q in the formula (1-6) represents An integer from 0 to 6 is shown.
The present invention is described in detail below.

The inventors of the present invention have said formula (1-1), formula (1-2), formula (1-3), formula (1-4), formula (1-5), and formula The cyclic imide compound represented by (1-6) (hereinafter also referred to as “cyclic imide compound according to the present invention”) is a low LUMO that is susceptible to electrochemical reduction due to the influence of a carbonyl group bonded to nitrogen. It was found to be energy stable and chemically stable. Therefore, the present inventors include a non-aqueous electrolyte containing an additive for a non-aqueous electrolyte containing the cyclic imide compound according to the present invention, and further adding the non-aqueous electrolyte to a power storage device such as a non-aqueous electrolyte secondary battery. When used for the above, it has been found that stable SEI can be formed on the electrode surface to improve battery characteristics such as cycle characteristics, charge / discharge capacity, and internal resistance, and the present invention has been completed.

The reason why the cyclic imide compound according to the present invention improves battery characteristics such as cycle characteristics, charge / discharge capacity, high-temperature storage characteristics, gas generation suppression, and reduction of internal resistance as an additive for non-aqueous electrolytes is not clear. It is considered as follows. The cyclic imide compound according to the present invention is considered to open the cyclic imide when subjected to electrochemical reduction, and to form SEI containing a large number of polar groups including nitrogen atoms, oxygen atoms and the like. Such SEI containing a large number of polar groups containing nitrogen atom, oxygen atom and the like exhibits excellent ionic conductivity and is electrochemically stable, and thus is considered to be a very high performance SEI. Moreover, although not certain, the cyclic imide compound according to the present invention has three carbonyl groups bonded to the nitrogen atom, and the electron density of nitrogen is low. Therefore, an electrochemical reduction reaction is performed on the negative electrode surface. It is easy to receive. As a result, it is considered that electrochemical reductive decomposition occurs easily and it is easy to form SEI on the negative electrode surface. On the other hand, when an alkyl group or the like is directly bonded to the nitrogen atom, it is difficult to undergo a reduction reaction on the negative electrode surface, and as a result, it is considered that SEI is difficult to form. Moreover, when the number of carbonyl groups bonded to the nitrogen atom is 2 or less, there is a possibility that a sufficient effect is not exhibited.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula R ^{9 in} (1-5) and R ¹¹ in formula (1-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms or an optionally substituted carbon number. 2 to 4 alkenyl groups, optionally substituted alkoxy groups having 1 to 4 carbon atoms, optionally substituted phenyl groups, optionally substituted phenoxy groups, optionally substituted benzyl groups, substituted A benzyloxy group which may be substituted, an alkenyloxy group having 2 to 6 carbon atoms which may be substituted, or an NR ¹³ R ¹⁴ group, wherein R ¹³ and R ¹⁴ are each independently a hydrogen atom, Optionally substituted alkyl group having 1 to 4 carbon atoms, optionally substituted carbon number 2 to 4 alkenyl groups, an optionally substituted phenyl group, or an optionally substituted benzyl group. Among them, R ¹ , R ³ , R ⁵ , R ⁷ , R ⁹ , and R ¹¹ are more susceptible to electrochemical reduction reaction and can form good SEI. A good alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenoxy group, an unsubstituted benzyloxy group, an optionally substituted alkenyloxy group having 2 to 4 carbon atoms, or R ¹³ and R ¹⁴ are each An NR ¹³ R ¹⁴ group which is an optionally substituted alkyl group having 1 to 4 carbon atoms or an optionally substituted benzyl group is preferable.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) are substituted alkyl groups having 1 to 4 carbon atoms, substituted alkenyl groups having 2 to 4 carbon atoms, The substituted alkoxy group having 1 to 4 carbon atoms, the substituted alkenyloxy group having 2 to 6 carbon atoms, the alkyl group having 1 to 4 carbon atoms in which at least one of R ¹³ and R ¹⁴ is substituted, or a substituted group; In the case of the NR ¹³ R ¹⁴ group which is an alkenyl group having 2 to 4 carbon atoms, examples of the substituent include a halogen atom. Among these, a halogen atom is preferable, and a fluorine atom is more preferable because it exhibits low LUMO energy that is easily subjected to electrochemical reduction.
R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), R ⁹ in the formula (1-5) and R ¹¹ in the formula (1-6) are a substituted phenyl group, a substituted phenoxy group, a substituted benzyl group, a substituted benzyloxy Group, or when at least one of R ¹³ and R ¹⁴ is a substituted phenyl group or a substituted benzyl group NR ¹³ R ¹⁴ group, examples of the substituent include alkyl having 1 to 4 carbon atoms Group, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, and the like. Among these, a halogen atom is preferable, and a fluorine atom is more preferable because it exhibits low LUMO energy that is easily subjected to electrochemical reduction.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted alkyl group represented by R ^{9 in} (1-5) and R ¹¹ in the above formula (1-6) include a methyl group, ethyl Group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, monofluoromethyl group, 2-monofluoroethyl group, 3-monofluoropropyl group, 4-monofluorobutyl group, difluoro Methyl group, 2,2-difluoroethyl group, 3,3-difluoropropyl group, 4,4-difluorobutyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, 3,3,3-trimethyl Fluoropropyl group, 4,4,4-trifluorobuty Group, 1,1,2,2,2-pentafluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 3,3,4,4,4-pentafluorobutyl group and the like. .

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted alkenyl group having 2 to 4 carbon atoms represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include, for example, vinyl group, allyl Group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, isobutenyl group and the like. Of these, an allyl group is preferable.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted alkoxy group having 1 to 4 carbon atoms represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include, for example, a methoxy group, ethoxy Group, n-propoxy group, n-butoxy group, trifluoromethoxy group, 2,2,2-trifluoroethyloxy group, 1,1,2,2,2-pentafluoroethyloxy group and the like. Of these, an ethoxy group and a 2,2,2-trifluoroethyloxy group are preferable.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted phenyl group represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include a phenyl group, a 2-methylphenyl group, 3 -Methylphenyl group, 4-methylphenyl group, 2-ethylphenyl group, 3-ethylphenyl group, 4-ethylphenyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 2-ethoxy Phenyl group, 3-ethoxyphenyl group, 4-ethoxyphenyl group, 2- (dimethylamino) phenyl group, 3- (dimethylamino) phenyl group, 4- (dimethylamino) phenyl group, 2-fluorophenyl group, 3- Fluorophenyl group 4-fluorophenyl group, 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2-bromophenyl group, 3-bromophenyl group, a 4-bromophenyl group. Of these, a phenyl group, a 2-fluorophenyl group, a 3-fluorophenyl group, and a 4-fluorophenyl group are preferable because they exhibit low LUMO energy that is easily subjected to electrochemical reduction.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted phenoxy group represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include a phenoxy group, a 2-methylphenoxy group, 3 -Methylphenoxy group, 4-methylphenoxy group, 2-ethylphenoxy group, 3-ethylphenoxy group, 4-ethylphenoxy group, 2-methoxyphenoxy group, 3-methoxyphenoxy group, 4-methoxyphenoxy group, 2-ethoxy Phenoxy group, 3-ethoxyphenoxy group, 4-ethoxyphenoxy group, 2- (dimethylamino) phenoxy group, 3- (dimethylamino) phenoxy group, 4- (dimethylamino) phenoxy group, 2-fluoro Enoxy group, 3-fluorophenoxy group, 4-fluorophenoxy group, 2-chlorophenoxy group, 3-chlorophenoxy group, 4-chlorophenoxy group, 2-bromophenoxy group, 3-bromophenoxy group, 4-bromophenoxy group Etc. Among these, a phenoxy group, a 4-methoxyphenoxy group, and a 4-fluorophenoxy group are preferable because they exhibit low LUMO energy that is easily subjected to electrochemical reduction.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted benzyl group represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include a benzyl group, a 2-methylbenzyl group, 3 -Methylbenzyl group, 4-methylbenzyl group, 2-ethylbenzyl group, 3-ethylbenzyl group, 4-ethylbenzyl group, 2-methoxybenzyl group, 3-methoxybenzyl group, 4-methoxybenzyl group, 2-ethoxy Benzyl group, 3-ethoxybenzyl group, 4-ethoxybenzyl group, 2- (dimethylamino) benzyl group, 3- (dimethylamino) benzyl group, 4- (dimethylamino) benzyl group, 2-fluorobenzyl group, 3- Fluorobenzyl group 4-fluorobenzyl group, 2-chlorobenzyl group, 3-chlorobenzyl group, 4-chlorobenzyl group, 2-bromobenzyl group, 3-bromobenzyl group, 4-bromobenzyl group, and the like. Of these, a benzyl group, a 4-methoxybenzyl group, and a 4-fluorobenzyl group are preferable because they exhibit low LUMO energy that is susceptible to electrochemical reduction.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the optionally substituted benzyloxy group represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include a benzyloxy group, 2-methylbenzyloxy Group, 3-methylbenzyloxy group, 4-methylbenzyloxy group, 2-ethylbenzyloxy group, 3-ethylbenzyloxy group, 4-ethylbenzyloxy group, 2-methoxybenzyloxy group, 3-methoxybenzyloxy group 4-methoxybenzyloxy group, 2-ethoxybenzyloxy group, 3-ethoxybenzyloxy group, 4-ethoxybenzyloxy group, 2- (dimethylamino) benzyloxy group, 3- (dimethylamino) base Zyloxy group, 4- (dimethylamino) benzyloxy group, 2-fluorobenzyloxy group, 3-fluorobenzyloxy group, 4-fluorobenzyloxy group, 2-chlorobenzyloxy group, 3-chlorobenzyloxy group, 4- Examples include chlorobenzyloxy group, 2-bromobenzyloxy group, 3-bromobenzyloxy group, 4-bromobenzyloxy group and the like. Of these, a benzyloxy group, a 4-methoxybenzyloxy group, and a 4-fluorobenzyloxy group are preferable because they exhibit low LUMO energy that is susceptible to electrochemical reduction.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula The optionally substituted alkenyloxy group having 2 to 6 carbon atoms represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) is, for example, 2-propenyl Examples thereof include an oxy group, a 1-methyl-2-propenyloxy group, a 2-methyl-2-propenyloxy group, a 2-butenyloxy group, a 3-butenyloxy group, a 2-hexenyloxy group, and a 5-hexenyloxy group. Of these, a 2-propenyloxy group and a 2-butenyloxy group are preferable because they exhibit low LUMO energy that is susceptible to electrochemical reduction.

R ¹ in the formula (1-1), R ³ in the formula (1-2), R ^{5 in} the formula (1-3), R ⁷ in the formula (1-4), the formula Examples of the NR ¹³ R ¹⁴ group represented by R ^{9 in} (1-5) and R ¹¹ in the formula (1-6) include an N, N-dimethylamino group, N, N-diethylamino group, and the like. Group, N-methyl-N-benzylamino group, N-methyl-N-phenylamino group, N, N-dibenzylamino group, N, N-diphenylamino group and the like. Of these, an N, N-dimethylamino group and an N-methyl-N-benzylamino group are preferable.

R ² in the formula (1-1), R ⁴ in the formula (1-2), R ^{6 in} the formula (1-3), R ⁸ in the formula (1-4), the formula R ^{10 in} (1-5) and R ¹² in the formula (1-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms or an optionally substituted carbon number. 1 to 4 alkoxy groups or a halogen atom. In the formula (1-1), l represents an integer of 0 to 4, in the formula (1-2), m represents an integer of 0 to 2, and in the formula (1-3), n represents 0. In the formula (1-4) represents an integer of 0 to 4, p in the formula (1-5) represents an integer of 0 to 4, and in the formula (1-6) Q in q represents an integer of 0 to 6.

R ² in the formula (1-1), R ⁴ in the formula (1-2), R ^{6 in} the formula (1-3), R ⁸ in the formula (1-4), the formula Examples of the optionally substituted alkyl group represented by R ^{10 in} (1-5) and R ¹² in the above formula (1-6) include a methyl group, ethyl Group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group and the like. Of these, a methyl group is preferable from the viewpoints of availability and reactivity.

R ² in the formula (1-1), R ⁴ in the formula (1-2), R ^{6 in} the formula (1-3), R ⁸ in the formula (1-4), the formula Examples of the optionally substituted alkoxy group having 1 to 4 carbon atoms represented by R ^{10 in} (1-5) and R ¹² in the formula (1-6) include, for example, a methoxy group, ethoxy Group, n-propoxy group, n-butoxy group and the like. Of these, a methoxy group is preferred from the viewpoints of availability and reactivity.

R ² in the formula (1-1), R ⁴ in the formula (1-2), R ^{6 in} the formula (1-3), R ⁸ in the formula (1-4), the formula Examples of the halogen atom represented by R ^{10 in} (1-5) and R ¹² in the above formula (1-6) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Of these, a chlorine atom is preferable from the viewpoint of availability, reactivity, and the like.

In the formula (1-1), l is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0 from the viewpoints of availability, reactivity, and the like.
When l in the formula (1-1) is 1, the preferred substitution position of R ² is the 4-position, and the preferred substitution positions when l is 2 are the 4-position and 5-position.
When l in the formula (1-1) is an integer of 2 to 4, each R ² may be the same or different.

M in the formula (1-2) is preferably 0 or 1, and more preferably 0.
When m in the formula (1-2) is 2, two R ^{4 s} may be the same or different.

In the formula (1-3), n is preferably 0 or 1, and more preferably 0.
When n in the formula (1-3) is 2, two R ^{6 s} may be the same or different.

In the formula (1-4), o is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0 from the viewpoints of availability and reactivity.
When o in the formula (1-4) is an integer of 2 to 4, each R ⁸ may be the same or different.

In the formula (1-5), p is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0 from the viewpoints of availability, reactivity, and the like.
When p in the formula (1-5) is an integer of 2 to 4, each R ¹⁰ may be the same or different.

Q in the formula (1-6) is preferably 0 to 2, more preferably 0 to 1, and still more preferably 0 from the viewpoints of availability and reactivity.
When q in the formula (1-6) is an integer of 2 to 6, each R ¹² may be the same or different.

Among the cyclic imide compounds according to the present invention, examples of the compound represented by the formula (1-1) include N-benzoylphthalimide, N- (phenoxycarbonyl) phthalimide, N-acetylphthalimide, and N- (methoxycarbonyl). ) Phthalimide, N-propanoylphthalimide, N- (ethoxycarbonyl) phthalimide, N-butanoylphthalimide, N- (propoxycarbonyl) phthalimide, N- (2-propenyloxycarbonyl) phthalimide, N-benzoyl-4-methylphthalimide N- (phenoxycarbonyl) -4-methylphthalimide, N-acetyl-4-methylphthalimide, N- (methoxycarbonyl) -4-methylphthalimide, N-propanoyl-4-methylphthalimide, N- (ethoxycarbonyl) -4-methylphthalimide, N-butanoyl-4-methylphthalimide, N- (propoxycarbonyl) -4-methylphthalimide, N-benzoyl-5-methylphthalimide, N- (phenoxycarbonyl) -5-methylphthalimide, N- Acetyl-5-methylphthalimide, N- (methoxycarbonyl) -5-methylphthalimide, N-propanoyl-5-methylphthalimide, N- (ethoxycarbonyl) -5-methylphthalimide, N-butanoyl-5-methylphthalimide, N -(Propoxycarbonyl) -5-methylphthalimide, N- (N ', N'-dimethylaminocarbonyl) phthalimide, N- (N'-methyl-N'-benzylaminocarbonyl) phthalimide and the like.

Among the cyclic imide compounds according to the present invention, examples of the compound represented by the formula (1-2) include N-benzoylmaleimide, N- (phenoxycarbonyl) maleimide, N-acetylmaleimide, N- (methoxycarbonyl). ) Maleimide, N-propanoylmaleimide, N- (ethoxycarbonyl) maleimide, N-butanoylmaleimide, N- (propoxycarbonyl) maleimide, N- (2-propenyloxycarbonyl) maleimide, N- (N ′, N ′ -Dimethylaminocarbonyl) maleimide, N- (N′-methyl-N′-benzylaminocarbonyl) maleimide and the like.

Among the cyclic imide compounds according to the present invention, examples of the compound represented by the formula (1-3) include N-benzoylsuccinimide, N- (phenoxycarbonyl) succinimide, and N-acetylsuccinimide. N- (methoxycarbonyl) succinimide, N-propanoyl succinimide, N- (ethoxycarbonyl) succinimide, N-butanoyl succinimide, N- (propoxycarbonyl) succinimide, N- ( 2-propenyloxycarbonyl) succinimide, N- (N ′, N′-dimethylaminocarbonyl) succinimide, N- (N′-methyl-N′-benzylaminocarbonyl) succinimide and the like.

Among the cyclic imide compounds according to the present invention, examples of the compound represented by the formula (1-4) include N-benzoylhexahydrophthalimide, N- (phenoxycarbonyl) hexahydrophthalimide, and N-acetylhexahydrophthalimide. N- (methoxycarbonyl) hexahydrophthalimide, N-propanoylhexahydrophthalimide, N- (ethoxycarbonyl) hexahydrophthalimide, N-butanoylhexahydrophthalimide, N- (propoxycarbonyl) hexahydrophthalimide, N- ( 2-propenyloxycarbonyl) hexahydrophthalimide, N-benzoyl-4-methylhexahydrophthalimide, N- (phenoxycarbonyl) -4-methylhexahydrophthalimide, N-acetyl-4-methyl Xahydrophthalimide, N- (methoxycarbonyl) -4-methylhexahydrophthalimide, N-propanoyl-4-methylhexahydrophthalimide, N- (ethoxycarbonyl) -4-methylhexahydrophthalimide, N-butanoyl-4-methyl Hexahydrophthalimide, N- (propoxycarbonyl) -4-methylhexahydrophthalimide, N-benzoyl-5-methylhexahydrophthalimide, N- (phenoxycarbonyl) -5-methylhexahydrophthalimide, N-acetyl-5-methyl Hexahydrophthalimide, N- (methoxycarbonyl) -5-methylhexahydrophthalimide, N-propanoyl-5-methylhexahydrophthalimide, N- (ethoxycarbonyl) -5-methylhexahydrophthal Imido, N-butanoyl-5-methylhexahydrophthalimide, N- (propoxycarbonyl) -5-methylhexahydrophthalimide, N- (N ', N'-dimethylaminocarbonyl) hexahydrophthalimide, N- (N'- Methyl-N′-benzylaminocarbonyl) hexahydrophthalimide and the like.

Among the cyclic imide compounds according to the present invention, examples of the compound represented by the formula (1-5) include N-benzoyl-1,2,3,6-tetrahydrophthalimide, N- (phenoxycarbonyl) -1 , 2,3,6-tetrahydrophthalimide, N-acetyl-1,2,3,6-tetrahydrophthalimide, N- (methoxycarbonyl) -1,2,3,6-tetrahydrophthalimide, N-propanoyl-1,2 , 3,6-tetrahydrophthalimide, N- (ethoxycarbonyl) -1,2,3,6-tetrahydrophthalimide, N-butanoyl-1,2,3,6-tetrahydrophthalimide, N- (propoxycarbonyl) -1, 2,3,6-tetrahydrophthalimide, N- (2-propenyloxycarbonyl) -1,2,3,6-tetra Drophthalimide, N-benzoyl-4-methyl-1,2,3,6-tetrahydrophthalimide, N- (phenoxycarbonyl) -4-methyl-1,2,3,6-tetrahydrophthalimide, N-acetyl-4- Methyl-1,2,3,6-tetrahydrophthalimide, N- (methoxycarbonyl) -4-methyl-1,2,3,6-tetrahydrophthalimide, N-propanoyl-4-methyl-1,2,3,6 -Tetrahydrophthalimide, N- (ethoxycarbonyl) -4-methyl-1,2,3,6-tetrahydrophthalimide, N-butanoyl-4-methyl-1,2,3,6-tetrahydrophthalimide, N- (propoxycarbonyl) ) -4-Methyl-1,2,3,6-tetrahydrophthalimide, N-benzoyl-5-methyl-1,2 3,6-tetrahydrophthalimide, N- (phenoxycarbonyl) -5-methyl-1,2,3,6-tetrahydrophthalimide, N-acetyl-5-methyl-1,2,3,6-tetrahydrophthalimide, N- (Methoxycarbonyl) -5-methyl-1,2,3,6-tetrahydrophthalimide, N-propanoyl-5-methyl-1,2,3,6-tetrahydrophthalimide, N- (ethoxycarbonyl) -5-methyl- 1,2,3,6-tetrahydrophthalimide, N-butanoyl-5-methyl-1,2,3,6-tetrahydrophthalimide, N- (propoxycarbonyl) -5-methyl-1,2,3,6-tetrahydro Phthalimide, N- (N ′, N′-dimethylaminocarbonyl) -1,2,3,6-tetrahydrophthalimide, N -(N'-methyl-N'-benzylaminocarbonyl) -1,2,3,6-tetrahydrophthalimide and the like.

Among the cyclic imide compounds according to the present invention, examples of the compound represented by the formula (1-6) include N-benzoylnaphthalimide, N- (phenoxycarbonyl) naphthalimide, N-acetylnaphthalimide, N- (Methoxycarbonyl) naphthalimide, N-propanoylnaphthalimide, N- (ethoxycarbonyl) naphthalimide, N-butanoylnaphthalimide, N- (propoxycarbonyl) naphthalimide, N- (2-propenyloxycarbonyl) naphthalimide N-benzoyl-4-methylnaphthalimide, N- (phenoxycarbonyl) -4-methylnaphthalimide, N-acetyl-4-methylnaphthalimide, N- (methoxycarbonyl) -4-methylnaphthalimide, N-propanoyl -4-Methylnaphthalimi N- (ethoxycarbonyl) -4-methylnaphthalimide, N-butanoyl-4-methylnaphthalimide, N- (N ′, N′-dimethylaminocarbonyl) naphthalimide, N- (N′-methyl-N ′ -Benzylaminocarbonyl) naphthalimide and the like.

The additive for non-aqueous electrolyte of the present invention includes a cyclic imide compound represented by the formula (1-1) and a cyclic imide compound represented by the formula (1-2) as the cyclic imide compound according to the present invention. A cyclic imide compound represented by the formula (1-3), a cyclic imide compound represented by the formula (1-4), a cyclic imide compound represented by the formula (1-5), and the formula It suffices to contain at least one of the cyclic imide compounds represented by (1-6), but it may contain two or more of them.
Among them, the non-aqueous electrolyte additive of the present invention is a compound represented by the following formula (2-1), a compound represented by the following formula (2-1) as a cyclic imide compound according to the present invention from the viewpoints of availability and reactivity. 2-2), a compound represented by the following formula (2-3), a compound represented by the following formula (2-4), a compound represented by the following formula (2-5), and It is preferable to contain at least one selected from the group consisting of compounds represented by the following formula (2-6), and a compound represented by the following formula (3-1), A compound represented by the following formula (3-3), a compound represented by the following formula (3-4), a compound represented by the following formula (3-5), and the following formula ( It is more preferable to contain at least one selected from the group consisting of compounds represented by 3-6).

Equation (2-1) in the ^{R 15,} ^{R 16} in the formula (2-2), ^{R 17} in the formula (2-3), ^{R 18} in the formula (2-4), the formula (2-5) R ¹⁹ in the formula and R ²⁰ in the formula (2-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms and an optionally substituted alkenyl group having 2 to 4 carbon atoms. , An optionally substituted alkoxy group having 1 to 4 carbon atoms, an optionally substituted phenyl group, an optionally substituted phenoxy group, an optionally substituted benzyl group, an optionally substituted benzyl An oxy group, an optionally substituted alkenyloxy group having 2 to 4 carbon atoms, or an NR ¹³ R ¹⁴ group, wherein R ¹³ and R ¹⁴ are each independently a hydrogen atom or an optionally substituted carbon; An alkyl group having 1 to 4 carbon atoms and an alkenyl having 2 to 4 carbon atoms which may be substituted An nyl group, an optionally substituted phenyl group, or an optionally substituted benzyl group is shown.

R ²¹ in formula (3-1), R ²² in formula (3-2), R ²³ in formula (3-3), R ²⁴ in formula (3-4), formula (3-5) R ²⁵ in the formula and R ²⁶ in the formula (3-6) each represent an optionally substituted alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenoxy group, or an unsubstituted benzyloxy group Represents an optionally substituted alkenyloxy group having 2 to 4 carbon atoms or an NR ¹³ R ¹⁴ group, and R ¹³ and R ¹⁴ each independently represents an optionally substituted 1 to 4 carbon atom An alkyl group or an optionally substituted benzyl group is shown.

R ¹⁵ in the formula (2-1), R ¹⁶ in the formula (2-2), R ¹⁷ in the formula (2-3), R ¹⁸ in the formula (2-4), the formula R ^{19 in} (2-5) and R ²⁰ in the above formula (2-6), optionally substituted alkyl group having 1 to 4 carbon atoms, optionally substituted carbon number 2 to 4 alkenyl groups, optionally substituted alkoxy groups having 1 to 4 carbon atoms, optionally substituted phenyl groups, optionally substituted phenoxy groups, optionally substituted benzyl groups, substituted The optionally substituted benzyloxy group, the optionally substituted alkenyloxy group having 2 to 4 carbon atoms, and the NR ¹³ R ¹⁴ group are represented by R ¹ in the above formula (1-1), (1-2) in ^{R 3,} ^{R 5} in the formula (1-3) in the formula (1-4) in R ^7, the formula (1-5) in ^{R 9,} and the formula (1-6) the same as those exemplified in ^{R 11,} or, the corresponding ones of the number of carbon atoms among those shown該例Can be mentioned.
R ²¹ in the formula (3-1), R ^{22 in} the formula (3-2), R ²³ in the formula (3-3), R ²⁴ in the formula (3-4), R ²⁵ in the above formula (3-5) and R ²⁶ in the above formula (3-6), an optionally substituted alkoxy group having 1 to 4 carbon atoms, an optionally substituted carbon number Examples of the alkenyloxy group of 2 to 4 and the NR ¹³ R ¹⁴ group include R ¹ in the formula (1-1), R ³ in the formula (1-2), and the formula (1-3), respectively. ^{R 5} in the ^{R 7} in the formula (1-4), the formula (1-5) in ^{R 9,} and, the same as those exemplified in ^{R 11} in the formula (1-6), Or the thing corresponding to carbon number is mentioned among this illustrated thing.

Examples of the method for producing the cyclic imide compound according to the present invention include a method of reacting a corresponding cyclic imide compound with a halide.
Specifically, for example, in the case of producing a compound (N- (phenoxycarbonyl) phthalimide) in which R ¹ is a phenoxy group and l is 0 in the formula (1-1), phthalimide and triethylamine are used as an organic solvent. Then, after adding phenyl chloroformate dropwise and stirring at room temperature for 2 hours, washing with water, crystallization, filtration, and the like can be used.

The cyclic imide compound according to the present invention has a preferred lower limit of the lowest unoccupied molecular orbital (LUMO) energy of −3.1 eV and a preferred upper limit of 0.0 eV. When the LUMO energy is less than −3.1 eV, excessive decomposition may occur, and a film showing high resistance may be formed on the negative electrode surface. When the LUMO energy exceeds 0.0 eV, stable SEI may not be formed on the negative electrode surface. A more preferable lower limit of the LUMO energy is −3.0 eV, and a more preferable upper limit is −0.5 eV.
The “lowest unoccupied molecular orbital (LUMO) energy” is calculated by combining the semi-empirical molecular orbital calculation method PM3 and the density functional method B3LYP method. Specifically, in the present invention, a value calculated using Gaussian 03 (Revision B.03, software manufactured by Gaussian, USA) is used.

Since the cyclic imide compound according to the present invention exhibits low LUMO energy that is susceptible to electrochemical reduction, the non-aqueous electrolyte additive of the present invention containing the cyclic imide compound according to the present invention is added to the non-aqueous electrolyte. When blended and used for power storage devices such as non-aqueous electrolyte secondary batteries, stable SEI can be formed on the electrode surface to improve battery characteristics such as cycle characteristics, charge / discharge capacity, and internal resistance. . In addition, since the cyclic imide compound according to the present invention is stable against moisture and temperature change, the additive for non-aqueous electrolyte of the present invention containing the cyclic imide compound according to the present invention can be used at room temperature for a long time. It is possible to save. Therefore, the non-aqueous electrolyte containing the non-aqueous electrolyte additive can withstand long-term storage and use.

The non-aqueous electrolyte containing the additive for non-aqueous electrolyte, the non-aqueous solvent, and the electrolyte of the present invention is also one aspect of the present invention.

The minimum with preferable content of the additive for nonaqueous electrolytes of this invention in the nonaqueous electrolyte of this invention is 0.005 mass%, and a preferable upper limit is 10 mass%. When the content of the additive for non-aqueous electrolyte of the present invention is less than 0.005% by mass, stable SEI is sufficiently obtained by electrolysis on the electrode surface when used in a non-aqueous electrolyte secondary battery or the like. May not be formed. When the content of the additive for non-aqueous electrolyte of the present invention exceeds 10% by mass, not only is it difficult to dissolve, but also the viscosity of the non-aqueous electrolyte increases, and it becomes impossible to ensure sufficient ion mobility. The electroconductivity etc. of electrolyte solution cannot fully be ensured, but when it uses for electrical storage devices, such as a nonaqueous electrolyte secondary battery, it may interfere with charging / discharging characteristics. The more preferable lower limit of the content of the additive for non-aqueous electrolyte of the present invention is 0.01% by mass. When the content of the additive for non-aqueous electrolyte of the present invention is in the above range, the effect of the present invention can be easily obtained, and in particular, the reductive decomposition reaction of the non-aqueous solvent occurring at high temperatures can be suppressed to a lower temperature. It is possible to improve capacity deterioration and gas generation due to storage underneath.
In addition, the additive for non-aqueous electrolytes of this invention may be used independently, and may be used in combination of 2 or more type. In addition, as for the total content when using 2 or more types of additives for non-aqueous electrolytes of this invention, a preferable minimum is 0.005 mass% and a preferable upper limit is 10 mass%.

The non-aqueous electrolyte of the present invention, if necessary, together with the additive for non-aqueous electrolyte of the present invention, such as vinylene carbonate (VC), fluoroethylene carbonate (FEC), 1,3-propane sultone (PS), etc. You may contain a general additive.

As the non-aqueous solvent, an aprotic solvent is preferable from the viewpoint of keeping the viscosity of the obtained non-aqueous electrolyte low. Among them, it contains at least one selected from the group consisting of cyclic carbonate, chain carbonate, aliphatic carboxylic acid ester, lactone, lactam, cyclic ether, chain ether, sulfone, nitrile, and halogen derivatives thereof. It is preferable. Of these, cyclic carbonates and chain carbonates are more preferably used.

Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate, butylene carbonate, and the like.
Examples of the chain carbonate include dimethyl carbonate, diethyl carbonate (DEC), and ethyl methyl carbonate.
Examples of the aliphatic carboxylic acid ester include methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, and methyl trimethyl acetate.
Examples of the lactone include γ-butyrolactone.
Examples of the lactam include ε-caprolactam and N-methylpyrrolidone.
Examples of the cyclic ether include tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane and the like.
Examples of the chain ether include 1,2-diethoxyethane, ethoxymethoxyethane, and the like.
Examples of the sulfone include sulfolane.
Examples of the nitrile include acetonitrile.
Examples of the halogen derivative include 4-fluoro-1,3-dioxolane-2-one, 4-chloro-1,3-dioxolan-2-one, 4,5-difluoro-1,3-dioxolane-2- ON etc. are mentioned.
These nonaqueous solvents may be used alone or in combination of two or more.
These nonaqueous solvents are preferably used for nonaqueous electrolyte secondary batteries such as lithium ion batteries, electric double layer capacitors such as lithium ion capacitors, and the like.

The electrolyte is preferably a lithium salt that serves as a source of lithium ions. Among _{_{_{them, LiAlCl 4, LiBF 4, LiPF}}} 6, LiClO 4, LiAsF 6 and is preferably at least one selected from the group consisting of LiSbF _6. Among them, LiBF ₄ and / or LiBF ₄ and / or LiF ₄ and / or from the viewpoint that the degree of dissociation is high, the ionic conductivity of the electrolytic solution can be increased, and further, the oxidation-reduction properties have an effect of suppressing performance deterioration of the electricity storage device due to long-term use. or more preferably LiPF _6. These electrolytes may be used alone or in combination of two or more.
Incidentally, the LiBF _4, if the LiPF ₆ is used as the non-aqueous solvent, preferably mixed one or more respective cyclic carbonate and chain carbonate is more preferable to mix ethylene carbonate and diethyl carbonate.

The preferable lower limit of the concentration of the electrolyte in the nonaqueous electrolytic solution of the present invention is 0.1 mol / L, and the preferable upper limit is 2.0 mol / L. When the concentration of the electrolyte is less than 0.1 mol / L, the conductivity of the non-aqueous electrolyte cannot be sufficiently ensured, and the discharge characteristics and the charge characteristics are hindered when used in an electricity storage device. Sometimes. When the concentration of the electrolyte exceeds 2.0 mol / L, the viscosity increases and the mobility of ions cannot be sufficiently ensured, so that the conductivity of the non-aqueous electrolyte cannot be sufficiently secured and When used in a device, the discharge characteristics and charging characteristics may be hindered. A more preferred lower limit of the electrolyte concentration is 0.5 mol / L, and a more preferred upper limit is 1.5 mol / L.

An electricity storage device including the non-aqueous electrolyte, positive electrode, and negative electrode of the present invention is also one aspect of the present invention. Examples of the electricity storage device include a non-aqueous electrolyte secondary battery and an electric double layer capacitor. Of these, lithium ion batteries and lithium ion capacitors are preferred.

FIG. 1 is a cross-sectional view schematically showing an example of the electricity storage device of the present invention.
In FIG. 1, a nonaqueous electrolyte secondary battery 1 according to an electricity storage device of the present invention includes a positive electrode plate 4 in which a positive electrode active material layer 3 is provided on one side of a positive electrode current collector 2, and a negative electrode current collector. A negative electrode plate 7 having a negative electrode active material layer 6 provided on one surface side of the body 5 is provided. The positive electrode plate 4 and the negative electrode plate 7 are disposed to face each other with a separator 9 provided in the non-aqueous electrolyte 8 and the non-aqueous electrolyte 8 of the present invention.
In FIG. 1, a non-aqueous electrolyte secondary battery is shown as the electricity storage device, but the electricity storage device of the present invention is not limited to this, and can be applied to other electricity storage devices such as electric double layer capacitors. .

As the positive electrode current collector 2 and the negative electrode current collector 5, for example, a metal foil made of a metal such as aluminum, copper, nickel, and stainless steel can be used.

As the positive electrode active material used for the positive electrode active material layer 3, a lithium-containing composite oxide is preferably used. For example, LiMnO ₂ , LiFeO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , Li ₂ FeSiO ₄ , LiNi _1/3 Co Examples thereof include lithium-containing composite oxides such as _1/3 Mn _1/3 O ₂ and LiFePO ₄ .

Examples of the negative electrode active material used for the negative electrode active material layer 6 include a material that can occlude and release lithium. Examples of such materials include carbon materials such as graphite and amorphous carbon, and oxide materials such as indium oxide, silicon oxide, tin oxide, zinc oxide, and lithium oxide.
In addition, as the negative electrode active material, lithium metal and a metal material capable of forming an alloy with lithium can be used. Examples of the metal capable of forming an alloy with lithium include Cu, Sn, Si, Co, Mn, Fe, Sb, Ag, and the like, and are composed of binary or ternary containing these metals and lithium. An alloy can also be used.
These negative electrode active materials may be used alone or in combination of two or more.

As the separator 9, for example, a porous film made of polyethylene, polypropylene, fluororesin, or the like can be used.

According to the present invention, when used in an electricity storage device, it has excellent storage stability and forms a stable SEI on the electrode surface to provide cycle characteristics, charge / discharge capacity, high temperature storage characteristics, gas generation suppression, and reduction of internal resistance. It is possible to provide an additive for a non-aqueous electrolyte that can improve battery characteristics such as the above. Moreover, according to this invention, the nonaqueous electrolyte using this additive for nonaqueous electrolytes, and the electrical storage device using this nonaqueous electrolyte can be provided.

It is sectional drawing which showed typically an example of the electrical storage device of this invention.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Example 1)
In a mixed non-aqueous solvent obtained by mixing ethylene carbonate (EC) and diethyl carbonate (DEC) at a volume composition ratio of EC: DEC = 30: 70, a concentration of 1.0 mol / L of LiPF ₆ as an electrolyte The content of the compound 1 shown in Table 1 as an additive for a non-aqueous electrolyte is 0.5% by mass with respect to the total amount of the solution composed of the mixed non-aqueous solvent and the electrolyte. Thus, a non-aqueous electrolyte was prepared.

(Example 2)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the content ratio of Compound 1 was 1.0% by mass.

(Example 3)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1, except that Compound 2 shown in Table 1 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

Example 4
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 3 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 5)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 4 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 6)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 5 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 7)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 6 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 8)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 7 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

Example 9
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 8 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 10)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 9 shown in Table 1 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 11)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 10 shown in Table 2 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

Example 12
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that Compound 11 shown in Table 2 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

(Example 13)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1, except that Compound 12 shown in Table 2 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

(Example 14)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 13 shown in Table 2 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 15)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 14 shown in Table 2 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 16)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 15 shown in Table 2 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 17)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 16 shown in Table 2 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Example 18)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that Compound 17 shown in Table 2 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

(Example 19)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1, except that Compound 18 shown in Table 2 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

(Comparative Example 1)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that Compound 1 was not used.

(Comparative Example 2)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that 1,3-propane sultone was added in such a manner that the content ratio was 1.0 mass% instead of Compound 1.

(Comparative Example 3)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that vinylene carbonate (VC) was added so as to have a content ratio of 1.0% by mass instead of Compound 1.

(Comparative Example 4)
A nonaqueous electrolytic solution was prepared in the same manner as in Comparative Example 3 except that the content of vinylene carbonate (VC) was 2.0% by mass.

(Comparative Example 5)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that fluoroethylene carbonate (FEC) was added so that the content ratio was 1.0% by mass instead of Compound 1.

(Comparative Example 6)
A nonaqueous electrolytic solution was prepared in the same manner as in Comparative Example 5 except that the content ratio of fluoroethylene carbonate (FEC) was 2.0% by mass.

(Comparative Example 7)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that phthalimide was added so that the content ratio was 1.0% by mass instead of Compound 1.

(Comparative Example 8)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that maleimide was added so that the content ratio was 1.0% by mass instead of Compound 1.

(Comparative Example 9)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that succinimide was added in such a manner that the content ratio was 1.0% by mass instead of Compound 1.

(Comparative Example 10)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 19 shown in Table 3 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Comparative Example 11)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1, except that Compound 20 shown in Table 3 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

(Comparative Example 12)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that Compound 21 shown in Table 3 was added instead of Compound 1 so that the content ratio was 1.0% by mass.

(Comparative Example 13)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the compound 22 shown in Table 3 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

(Comparative Example 14)
A nonaqueous electrolytic solution was prepared in the same manner as in Example 1, except that the compound 23 shown in Table 3 was added instead of the compound 1 so that the content ratio was 1.0% by mass.

<Evaluation>
(Measurement of LUMO energy)
For compounds 1-18 used in the examples, semi-empirical molecular orbital calculations were performed with Gaussian 03 software to measure LUMO (lowest unoccupied molecular orbital) energy. Tables 1 and 2 show LUMO energies of compounds 1 to 18 obtained by orbit calculation.

(Stability)
The compounds 1 to 18 used in the examples and the fluoroethylene carbonate (FEC) used in Comparative Examples 5 and 6 were stored for 90 days in a constant temperature and humidity environment at a temperature of 40 ± 2 ° C. and a humidity of 75 ± 5%. test carried out, ¹ H- measure nuclear magnetic resonance spectra ^{(1 H-NMR),} check the peak of each compound before and after the storage, the case where there is no peak change in ^{1 H-NMR} before and after storage "○" The stability was evaluated as “Δ” when a slight change in ¹ H-NMR peak was observed before and after storage, and “×” when a clear peak change in ¹ H-NMR was confirmed before and after storage. . The results are shown in Table 4.

As shown in Table 4, the fluoroethylene carbonate (FEC) used in Comparative Examples 5 and 6 was considered to be partially hydrolyzed and had poor stability. On the other hand, compounds 1 to 18 used in the examples were hardly changed and excellent in stability.

(Evaluation of discharge capacity maintenance ratio and internal resistance ratio)
Disperse uniformly in N-methyl-2-pyrrolidone (NMP) in which LiMn ₂ O ₄ as a positive electrode active material and carbon black as a conductivity imparting agent are dry-mixed and polyvinylidene fluoride (PVDF) is dissolved as a binder To prepare a slurry. The obtained slurry was applied on an aluminum metal foil (square shape, thickness 20 μm) serving as a positive electrode current collector, and then NMP was evaporated to prepare a positive electrode sheet. The solid content ratio in the obtained positive electrode sheet was a mass ratio of positive electrode active material: conductivity imparting agent: PVDF = 80: 10: 10.
On the other hand, as the negative electrode sheet, a commercially available graphite coated electrode sheet (manufactured by Hosen Co., Ltd.) was used.
In each of the nonaqueous electrolyte solutions obtained in Examples 1 to 19 and Comparative Examples 1 to 9, a negative electrode sheet and a positive electrode sheet were laminated via a separator made of polyethylene to produce a cylindrical secondary battery. .
Each cylindrical secondary battery obtained was charged at 25 ° C. with a charge rate of 0.3 C, a discharge rate of 0.3 C, a charge end voltage of 4.2 V, and a discharge end voltage of 2.5 V. A discharge cycle test was conducted. Tables 5 and 6 show the discharge capacity retention ratio (%) after 200 cycles and the internal resistance ratio after 200 cycles.
“Discharge capacity maintenance rate after 200 cycles (%)” is obtained by multiplying the value obtained by dividing discharge capacity (mAh) after 200 cycle test by discharge capacity (mAh) after 10 cycle test by 100. It is. The “internal resistance ratio after 200 cycles” is a relative value of the resistance after the 200 cycle test when the resistance before the cycle test is 1.

From Tables 5 and 6, the cylindrical secondary batteries using the non-aqueous electrolytes of Examples including the compounds 1 to 18 which are cyclic imide compounds according to the present invention are the non-aqueous electrolytes of Comparative Examples 1 to 9. It can be seen that the discharge capacity retention rate during the cycle test is higher than that of the used cylindrical secondary battery. Therefore, when the non-aqueous electrolyte of the example containing the cyclic imide compound according to the present invention as an additive for a non-aqueous electrolyte is used for a non-aqueous electrolyte secondary battery, the non-aqueous electrolyte of a comparative example is used. It can be seen that SEI that is stable with respect to the charge / discharge cycle is formed on the electrode surface of the nonaqueous electrolyte secondary battery. Moreover, since the non-aqueous electrolyte of an Example has a small internal resistance ratio, it turns out that the increase in internal resistance by the time of a cycle can be suppressed.

(Measurement of high-temperature storage characteristics and gas generation amount)
In N-methyl-2-pyrrolidone (NMP) in which lithium cobaltate (LiCoO ₂ ) as a positive electrode active material and carbon black as a conductivity imparting agent are dry-mixed and polyvinylidene fluoride (PVDF) is dissolved as a binder. The slurry was uniformly dispersed to prepare a slurry. The obtained slurry was applied to both surfaces of an aluminum metal foil (square shape, thickness 20 μm) serving as a positive electrode current collector, NMP was dried, and pressed to obtain a positive electrode. The solid content ratio in the obtained positive electrode sheet was a mass ratio, and was positive electrode active material: conductivity imparting agent: PVDF = 90: 5: 5.
On the other hand, graphite powder as a negative electrode active material and carbon black as a conductivity imparting agent are dry-mixed and uniformly dispersed in N-methyl-2-pyrrolidone (NMP) in which polyvinylidene fluoride (PVDF) is dissolved as a binder. To prepare a slurry. The obtained slurry was applied to one side of a copper foil (square shape, thickness 10 μm) serving as a negative electrode current collector, NMP was dried, and then pressed to obtain a negative electrode. The solid content ratio in the obtained negative electrode sheet was a mass ratio, and was negative electrode active material: conductivity imparting agent: PVDF = 93: 3: 4.
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, the positive electrode, the separator, and the negative electrode to produce a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness 40 μm) were coated with a resin layer while projecting positive and negative terminals, and then Examples 1 to 19 and Comparative Examples 1 to 14 Each non-aqueous electrolyte obtained in (1) was poured into a bag and vacuum sealed to produce a sheet-like non-aqueous electrolyte battery. Furthermore, in order to improve the adhesion between the electrodes, the sheet-like battery was sandwiched between glass plates and pressurized.
The obtained nonaqueous electrolyte battery was charged to 4.2 V at a current corresponding to 0.2 C at 25 ° C. and then discharged to 3 V at a current corresponding to 0.2 C for 3 cycles. The battery was stabilized.
Next, after charging to 4.2 V again at a charge rate of 0.3 C, high temperature storage at 60 ° C. for 168 hours was performed. Then, it cooled to room temperature, measured the volume by Archimedes method, and calculated | required the gas generation amount from the volume change before and behind a preservation | save. Further, the battery after high-temperature storage was discharged to 3.0 V with a current corresponding to 0.2 C to obtain the remaining capacity of the battery. Finally, after charging to 4.2 V at a current corresponding to 0.2 C, the operation of discharging to 0.2 V at 3 C was repeated twice, and the capacity indicated by the battery in the final discharge was taken as the battery recovery capacity. The ratios of the remaining capacity and the recovery capacity obtained above to the discharge capacity before storage were defined as the remaining capacity ratio (%) and the recovery capacity ratio (%), respectively. The results are shown in Tables 7 and 8.
From Tables 7 and 8, the non-aqueous electrolyte battery using the non-aqueous electrolyte solution of each example containing compounds 1 to 18 which are the cyclic imide compounds according to the present invention is a non-aqueous electrolyte solution using the non-aqueous electrolyte solution of the comparative example. Compared with an aqueous electrolyte battery, the amount of gas generated during high-temperature storage is low, and the remaining capacity and recovery capacity after high-temperature storage are excellent, so that high-temperature storage characteristics can be improved. In addition, when a compound having a structure similar to the cyclic imide compound according to the present invention (phthalimide, maleimide, succinimide, compounds 19 to 23) is used in place of the cyclic imide compound according to the present invention, the generated gas at high temperature storage Although a slight effect is seen in suppression and improvement of the remaining capacity and recovery capacity after high-temperature storage, it can be seen that it is insufficient as an additive.

DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery 2 Positive electrode collector 3 Positive electrode active material layer 4 Positive electrode plate 5 Negative electrode collector 6 Negative electrode active material layer 7 Negative electrode plate 8 Nonaqueous electrolyte 9 Separator

Claims

In the following formula (1-1), the following formula (1-2), the following formula (1-3), the following formula (1-4), the following formula (1-5), or the following formula (1-6) A non-aqueous electrolyte additive comprising a cyclic imide compound represented.

R 1 in formula (1-1), R 3 in formula (1-2), R 5 in formula (1-3), R 7 in formula (1-4), formula (1-5) R 9 in the formula and R 11 in the formula (1-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms and an optionally substituted alkenyl group having 2 to 4 carbon atoms. , An optionally substituted alkoxy group having 1 to 4 carbon atoms, an optionally substituted phenyl group, an optionally substituted phenoxy group, an optionally substituted benzyl group, an optionally substituted benzyl An oxy group, an optionally substituted alkenyloxy group having 2 to 6 carbon atoms, or an NR 13 R 14 group, wherein R 13 and R 14 are each independently a hydrogen atom or an optionally substituted carbon; An alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms which may be substituted, A phenyl group which may be substituted or a benzyl group which may be substituted is shown. R 2 in formula (1-1), R 4 in formula (1-2), R 6 in formula (1-3), R 8 in formula (1-4), formula (1-5) R 10 in the formula and R 12 in the formula (1-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms and an optionally substituted alkoxy group having 1 to 4 carbon atoms. Or a halogen atom. L in the formula (1-1) represents an integer of 0 to 4, m in the formula (1-2) represents an integer of 0 to 2, and n in the formula (1-3) represents 0 to 2. Represents an integer, o in the formula (1-4) represents an integer of 0 to 4, p in the formula (1-5) represents an integer of 0 to 4, and q in the formula (1-6) represents An integer from 0 to 6 is shown.
As the cyclic imide compound, a compound represented by the following formula (2-1), a compound represented by the following formula (2-2), a compound represented by the following formula (2-3), the following formula (2-4) And at least one selected from the group consisting of a compound represented by the following formula (2-5) and a compound represented by the following formula (2-6). The additive for non-aqueous electrolyte described.
Equation (2-1) in the R 15, R 16 in the formula (2-2), R 17 in the formula (2-3), R 18 in the formula (2-4), the formula (2-5) R 19 in the formula and R 20 in the formula (2-6) are each an optionally substituted alkyl group having 1 to 4 carbon atoms and an optionally substituted alkenyl group having 2 to 4 carbon atoms. , An optionally substituted alkoxy group having 1 to 4 carbon atoms, an optionally substituted phenyl group, an optionally substituted phenoxy group, an optionally substituted benzyl group, an optionally substituted benzyl An oxy group, an optionally substituted alkenyloxy group having 2 to 4 carbon atoms, or an NR 13 R 14 group, wherein R 13 and R 14 are each independently a hydrogen atom or an optionally substituted carbon; An alkyl group having 1 to 4 carbon atoms and an alkenyl having 2 to 4 carbon atoms which may be substituted An nyl group, an optionally substituted phenyl group, or an optionally substituted benzyl group is shown.
As the cyclic imide compound, a compound represented by the following formula (3-1), a compound represented by the following formula (3-2), a compound represented by the following formula (3-3), and the following formula (3-4) And at least one selected from the group consisting of a compound represented by the following formula (3-5) and a compound represented by the following formula (3-6). Or the additive for non-aqueous electrolytes of 2.

R 21 in formula (3-1), R 22 in formula (3-2), R 23 in formula (3-3), R 24 in formula (3-4), formula (3-5) R 25 in the formula and R 26 in the formula (3-6) each represent an optionally substituted alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenoxy group, or an unsubstituted benzyloxy group Represents an optionally substituted alkenyloxy group having 2 to 4 carbon atoms or an NR 13 R 14 group, and R 13 and R 14 each independently represents an optionally substituted 1 to 4 carbon atom An alkyl group or an optionally substituted benzyl group is shown.
A nonaqueous electrolytic solution comprising the additive for nonaqueous electrolytic solution according to claim 1, 2, or 3, a nonaqueous solvent, and an electrolyte.
The nonaqueous electrolytic solution according to claim 4, wherein the nonaqueous solvent is an aprotic solvent.
The aprotic solvent is at least one selected from the group consisting of cyclic carbonate, chain carbonate, aliphatic carboxylic acid ester, lactone, lactam, cyclic ether, chain ether, sulfone, nitrile, and halogen derivatives thereof. The non-aqueous electrolyte according to claim 5.
The nonaqueous electrolytic solution according to claim 4, 5 or 6, wherein the electrolyte contains a lithium salt.
Lithium salt, LiAlCl 4, LiBF 4, LiPF 6, LiClO 4, LiAsF 6, and the nonaqueous electrolytic solution according to claim 7, wherein at least one selected from the group consisting of LiSbF 6.
The electrical storage device provided with the non-aqueous electrolyte of Claim 4, 5, 6, 7 or 8, a positive electrode, and a negative electrode.
The electricity storage device according to claim 9, wherein the electricity storage device is a lithium ion battery.
The power storage device according to claim 9, wherein the power storage device is a lithium ion capacitor.